Originally Posted by Groundhogal:
“Was it just me or did the contestants questions seem quite hard today?”
Originally Posted by richie4eva:
“To quote Chris Tarrant:"They are only easy if you know the answers"”
That's true (but also see the 'Stupid answers...' thread!)
It's also probably true that if you play along with the show every day, particular with the two Final Chases, I'd think you'll usually score roughly the same every day, plus or minus a couple. If you exceed expectation, then you'll feel you played very well; if you fail to meet expectation, you'll probably feel the questions were much harder than usual (this is a form of Attribution Bias

)
I'd hope to get 12 on a final chase, +/- 2. Once or twice over the years I've had 18, when every question fell into an area I just happened to know. I got only 5 on one of the shows earlier this week! (Anne's show, IIRC)
However, some questions come up time and again, and people know them
because they are common questions, just like many players on Countdown know words like GHERAO and LODESTAR, most Scrabble players know DZHO and QAT, etc. before they even start. Then there are are facts "that everybody should know" (but don't, alarmingly) e.g. the name of the current Prime Minister, the reigning monarch, the number of months in a year ...
If none of those frequently asked questions come up, then I think it's fair to say that the questions were "harder than usual" on the basis that there were fewer gimmes... I've almost convinced myself that that's true.